2025A&A...693L..18B -
Astronomy and Astrophysics, volume 693L18 (2025/1-1)
Spectroscopic confirmation of a dust-obscured, possibly metal-rich dwarf galaxy at z ∼ 5.
BISIGELLO L., GANDOLFI G., FELTRE A., ARRABAL HARO P., CALABRO A., CLERI N.J., COSTANTIN L., GIRARDI G., GIULIETTI M., GRAZIAN A., GRUPPIONI C., HATHI N.P., HOLWERDA B.W., LLERENA M., LUCAS R.A., PACUCCI F., PRANDONI I., RODIGHIERO G., SEILLE L.-M., WILKINS S.M., BAGLEY M., DICKINSON M., FINKELSTEIN S.L., KARTALTEPE J., KOEKEMOER A.M., PAPOVICH C. and PIRZKAL N.
Abstract (from CDS):
We present the first spectroscopic confirmation of a dust-obscured dwarf galaxy, CEERS-14821. The analysis was performed by combining JWST NIRCam broadband photometry and NIRSpec/PRISM spectroscopic data. From the detection of multiple rest-frame optical lines, we derive that CEERS-14821 is located at z = 4.883 ± 0.003. Moreover, from a secure detection of the Hα and Hβ, we derive that the galaxy has a dust extinction ranging from $ A_{V}=2.2_{-0.6}^{+0.5} $ to $ A_{V}=3.4_{-0.9}^{+0.7} $, depending on the assumed reddening law. This value is extremely large given that we estimated a low stellar mass, that is, $ \log_{10}(\mathrm{M}/\mathrm{M}_{\odot})=8.17_{-0.04}^{+0.05} $ or $ \log_{10}(\mathrm{M}/\mathrm{M}_{\odot})=8.65_{-0.05}^{+0.06} $, based on two different dust extinction laws. Moreover, the combination of different metallicity tracers and the spectro-photometric fit suggests that the galaxy may also be metal-rich, with 12 + log10(O/H)> 8.3, but a low metallicity value cannot be totally ruled out. The high metallicity value would be above the expectation based on the mass-metallicity relation. Both metallicity estimations are above the expectations based on the fundamental mass-metallicity relation since CEERS-14821 is going through a burst of star formation. The constraints on a possible active galactic nucleus presence are limited and loose, but they point towards a possible non-dominant contribution (fAGN < 0.5 with respect to the total dust luminosity). Based on the rest-frame optical images, this source has a size compatible with galaxies of similar stellar masses and at similar redshifts. Finally, CEERS-14821 may be part of a larger galaxy overdensity, but there are no other galaxies closely interacting with it (within 30 Mpc).
Abstract Copyright:
© The Authors 2025
Journal keyword(s):
galaxies: dwarf - galaxies: fundamental parameters - galaxies: ISM - galaxies: peculiar
Status at CDS
:
Examining the need for a new acronym. // All or part of tables of objects will be ingested in SIMBAD with priority 1.
Simbad objects:
1
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